Santorum is expected to appear on local news outlets later in the morning, followed by an 11 a.m. courthouse speech in rural southwestern Pennsylvania coal country, where his Italian immigrant grandfather once worked in the mines. He lost his last election five years ago to Democrat Robert Casey, 59 percent to 41 percent. The last president from the Keystone State was James Buchanan.

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"People are looking for someone that has stood by their principles in good times and bad -- 2006 was a bad time for Republicans and for Conservatives," Santorum said on his loss to Casey. "What I did, when I did it, people can say, you know what? He may have lost. He didn't flinch. He stood by what he believed in."

In a recent Gallup poll, only 2 percent of Republicans and Republican-leaning independents preferred Santorum to other possible presidential contenders, placing him third-to-last in a field of 12.

Speaking alongside other Republican leaders at the Faith and Freedom Conference this weekend, Santorum focused on his socially conservative record, including his opposition to abortion rights and same-sex marriage.

"I'm out there fighting for causes social conservatives care about, and they're not just social conservative causes," he said.